The embodiment relates to a wireless power transmitter. In more particular, the embodiment relates to a wireless power transmitter capable of improving power transmission efficiency between the wireless power transmitter and a wireless power receiver and reducing the amount of magnetic field that leaks to the outside.
A wireless power transmission or a wireless energy transfer refers to a technology of wirelessly transferring electric energy to desired devices. In the 1800's, an electric motor or a transformer employing the principle of electromagnetic induction has been extensively used and then a method for transmitting electrical energy by irradiating electromagnetic waves, such as radio waves or lasers, has been suggested. Actually, electrical toothbrushes or electrical razors, which are frequently used in daily life, are charged based on the principle of electromagnetic induction. Until now, the long-distance transmission using the magnetic induction, the resonance and the short-wavelength radio frequency has been used as the wireless energy transfer scheme.
Recently, among wireless power transmitting technologies, an energy transmitting scheme using resonance has been widely used.
Since an electric signal generated between the wireless power transmitter and the wireless power receiver is wirelessly transferred through coils in a wireless power transmitting scheme using resonance, a user may easily charge electronic appliances such as a portable device.
However, in the wireless power transmitting scheme using resonance, a magnetic field generated from a transmission side may be leaked to the outside. The leaked magnetic field may exert a bad influence upon human health.